1. Field of the Invention
This invention relates to the molding of metal objects such as battery plates or the like by a bottom gating process and especially to the efficient production of such objects while minimizing the trimming of flash and gate.
2. Brief Description of the Prior Art
After a study of applicant's own file preliminary to the filing of the present application, it is believed that the most relevant prior art is U.S. Pat. No. 1,809,289 patented June 9, 1931, which shows a mobile molten metal tank which is moved between stationary molds for producing battery grid plates by forcing the molten metal from the tank into the mold sections. However, as evidenced by the age of the prior art patent and the lack of real commercial usage of the bottom gating technique in the production of battery grid plates even to this date, the prior gating systems have had their disadvantages. One disadvantage is that it is extremely difficult to assure filling of the mold completely under the required pressurized conditions while still minimizing the formation of trim and flash. Often either incomplete grids are formed or else excessive trim and flash is formed.
In view of the difficulties with bottom gate molding, such molding generally has been used only for artistic or specialty items. Gravity flow top gate molding is normally used for such operations as the productions of battery grid plates.